Melt the butter and let it cool down. Warm the milk lukewarm. Stir yeast into it. Add flour, 25 g sugar, 1 egg and butter and work into a smooth dough. Cover and leave to rise in a warm place for about 30 minutes. In the meantime, sort out the fruit, wash and drain well. Mix the sour cream, 3 eggs, 50 g sugar and vanillin sugar.
Grease a baking dish (26 cm Ø) with removable bottom and sprinkle with flour. Lightly knead the yeast dough on a floured work surface, roll out round (28 cm Ø) and place in the mould. Press the dough at the edge. Spread 400 g fruit in it, pour the icing evenly over it. Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 30 minutes. Sprinkle with remaining fruit and bake for another 15 minutes. Serve dusted with icing sugar